Yes because they are sticking to featuring F Class products. You can throw the ME3 and ANA in there as well.. But we know F is dying at many airlines and of the over 800 777Ws delivered, less than 50 have left their original airline. The replacement cycle still hasn't really started.. How many of those carriers will continue to feature a large F class? That decision will loom large on who ultimately wins the battle between the two.
It's not First - it's Economy. The world's 777-300ER fleet is moving from 9-abreast to 10-abreast even on airlines that were staunchly (or considered by a.net to be staunchly) against such a move on the grounds of passenger comfort. As I noted up-thread, I believe that is being driven by a desire to lower CASM and raise (incremental) RASM.
Now the A350-1000 lowers CASM just by being a much more efficient frame than the 777-300ER, but Airbus themselves are now talking about making 10-abreast a "viable" option on the A350-1000 and I believe that could be driven by Airbus seriously considering that the 777-9's innate larger capacity is a positive point for the frame even for customers who are A350 operators.
Airbus can close this "capacity gap" by going to 10-abreast, but at lower comfort which runs counter to their advertising philosophy (though they will just shift the "blame" to the airlines just as Boeing has done). They can also close it by stretching the A350 yet again, though the belief Airbus can bring such a frame to market in volume in only a handful of years is, IMO, overly optimistic.
Personally, I don't see Airbus needing to close that "capacity gap" in the near term. The A350-1000's benefits are clear and compelling as-is and operators are responding to them by purchasing the plane. The A350-1000 and 777-9 look to be more "complimentary" frames than competitive ones and even then, the number of airlines that need both are probably relatively few. So I do not believe it is at all a case that Airbus must offer a direct competitor to the 777-9 or miss out on a significant number of sales.
IMO, this is very much NOT
an A340-600 / 777-300ER "winner takes (most) all" scenario. I believe it will be much more nuanced, with both OEMs playing to their respective strengths and using that to maximize their Average Sales Prices and not to try and cover each other as tightly as possible, which will just lower ASPs for both.
So the GE9x might not be in service until 2021 and your telling us BA could dump GE, in 2025, for the RR Ultrafan.
I'm saying that if the Ultrafan becomes super-compelling, Boeing can respond (though I do not believe Ultrafan will be customer-ready in 2025, anyway).
And one should not discount the money a 777-9 will earn and save over the years it would be in service before an UF A350-1000 would arrive.